I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to get cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity demand is low. I'm no longer heating by electric, but do run some computers 24/7. It's not totally clear whether this saves me money or costs me money, as I pay a higher price per unit during the expensive period, to compensate for the fact I get it cheap for 7 hours. But I run some computers 24/7. I guess I should do the maths and work it out. Apart from some heaters in the garage, which are very rarely used, I no longer heat with it. The time when the electric is cheap is set by a clock, which rotates once/day. It says on it "quartz" somewhere, so it must be regulated by a crystal and not from the 50 Hz supply, which would be pretty useless, as the clock would go wrong if there was ever a power failure. The clock has not been changed in the 17 years I've lived at my house, though the meter has on a couple of occasions. The clock used to keep accurate, but now it looses time about 30 minutes/day. I wrote a computer program to predict when the electric is cheap, so we can schedule when things like the washing machine, dishwasher, Hoover etc are used. Even cooking to a certain extent, if it's convenient, though our life does not revolve around the cheap electric. I'm wondering if this is a mechanical fault in the clock, or whether the crystal has developed a fault. It's clearly well outside any tolerance or aging process of any crystal - even the cheapest ones. I've not done any very extensive tests, but the error does not appear to be constant. Hence every month or so I need to produce a new table, as my predictions get less accurate with time. Since one can only read the clock to an accuracy of about 15 minutes, it's not easy to know how far it is out. Sometimes we hear the contactor go over, as this is supposed to then power the storage heaters, which we no long use. Dave

It is possible the crystal has succumbed to a mechanical fatigue. To check I used an old relay coil with a ferrite rod stuffed through it and tuned to 32.6khz. If you have a sensitive enough counter you may be able to measure this without an amp in line. (2% is a long way out !) It could also be the trimmer capacitor that has failed. I doubt there is much more mechanical, other than a dodgy solder joint. In all probability it will be the bane of all lovers of old electronics....the power supply electrolytic capacitors......remember battery quartz clocks run slow or fast as the batt runs out. Alan G3NYK --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> wrote: > From: Dr. David Kirkby <david.kirkby@onetel.net> > Subject: [time-nuts] Can a quartz crystal go off by 2% ? > To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> > Date: Monday, 28 December, 2009, 23:22 > I'm on the so-called 'Economy 7' > electric in the UK, where I'm supposed to get cheap electric > from 0030 to 0730 - i.e. a 7 hour period when electricity > demand is low. I'm no longer heating by electric, but do run > some computers 24/7. It's not totally clear whether this > saves me money or costs me money, as I pay a higher price > per unit during the expensive period, to compensate for the > fact I get it cheap for 7 hours. But I run some computers > 24/7. I guess I should do the maths and work it out. Apart > from some heaters in the garage, which are very rarely used, > I no longer heat with it. > > The time when the electric is cheap is set by a clock, > which rotates once/day. It says on it "quartz" somewhere, so > it must be regulated by a crystal and not from the 50 Hz > supply, which would be pretty useless, as the clock would go > wrong if there was ever a power failure. The clock has not > been changed in the 17 years I've lived at my house, though > the meter has on a couple of occasions. > > The clock used to keep accurate, but now it looses time > about 30 minutes/day. I wrote a computer program to predict > when the electric is cheap, so we can schedule when things > like the washing machine, dishwasher, Hoover etc are used. > Even cooking to a certain extent, if it's convenient, though > our life does not revolve around the cheap electric. > > I'm wondering if this is a mechanical fault in the clock, > or whether the crystal has developed a fault. It's clearly > well outside any tolerance or aging process of any crystal - > even the cheapest ones. > > I've not done any very extensive tests, but the error does > not appear to be constant. Hence every month or so I need to > produce a new table, as my predictions get less accurate > with time. Since one can only read the clock to an accuracy > of about 15 minutes, it's not easy to know how far it is > out. Sometimes we hear the contactor go over, as this is > supposed to then power the storage heaters, which we no long > use. > > Dave > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

ALAN MELIA wrote: > It is possible the crystal has succumbed to a mechanical fatigue. To check I used an old relay coil with a ferrite rod stuffed through it and tuned to 32.6khz. If you have a sensitive enough counter you may be able to measure this without an amp in line. (2% is a long way out !) It could also be the trimmer capacitor that has failed. I doubt there is much more mechanical, other than a dodgy solder joint. > In all probability it will be the bane of all lovers of old electronics....the power supply electrolytic capacitors......remember battery quartz clocks run slow or fast as the batt runs out. > Alan G3NYK It could be the battery is low. There clearly is a battery backup, and there is something on the clock which implies the holdover period is about 4 days. (I forget the exact wording). Clearly if there is a power failure, the clock must still rotate to keep accurate. I assume the battery is constantly charged by the incoming supply. Given the age of the battery (> 17 years), it is unlikely to be in good condition! But it should be charged all the time. But perhaps even when charged, its voltage is very different to what it should be. I would not have thought a trimmer cap going open-circuit could have induced a 2% change. That seems an awful lot. Thanks for the idea of the ferrite rod. Dave > --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> wrote: > >> From: Dr. David Kirkby <david.kirkby@onetel.net> >> Subject: [time-nuts] Can a quartz crystal go off by 2% ? >> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> >> Date: Monday, 28 December, 2009, 23:22 >> I'm on the so-called 'Economy 7' >> electric in the UK, where I'm supposed to get cheap electric >> from 0030 to 0730 - i.e. a 7 hour period when electricity >> demand is low. I'm no longer heating by electric, but do run >> some computers 24/7. It's not totally clear whether this >> saves me money or costs me money, as I pay a higher price >> per unit during the expensive period, to compensate for the >> fact I get it cheap for 7 hours. But I run some computers >> 24/7. I guess I should do the maths and work it out. Apart >> from some heaters in the garage, which are very rarely used, >> I no longer heat with it. >> >> The time when the electric is cheap is set by a clock, >> which rotates once/day. It says on it "quartz" somewhere, so >> it must be regulated by a crystal and not from the 50 Hz >> supply, which would be pretty useless, as the clock would go >> wrong if there was ever a power failure. The clock has not >> been changed in the 17 years I've lived at my house, though >> the meter has on a couple of occasions. >> >> The clock used to keep accurate, but now it looses time >> about 30 minutes/day. I wrote a computer program to predict >> when the electric is cheap, so we can schedule when things >> like the washing machine, dishwasher, Hoover etc are used. >> Even cooking to a certain extent, if it's convenient, though >> our life does not revolve around the cheap electric. >> >> I'm wondering if this is a mechanical fault in the clock, >> or whether the crystal has developed a fault. It's clearly >> well outside any tolerance or aging process of any crystal - >> even the cheapest ones. >> >> I've not done any very extensive tests, but the error does >> not appear to be constant. Hence every month or so I need to >> produce a new table, as my predictions get less accurate >> with time. Since one can only read the clock to an accuracy >> of about 15 minutes, it's not easy to know how far it is >> out. Sometimes we hear the contactor go over, as this is >> supposed to then power the storage heaters, which we no long >> use. >> >> Dave >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Dr. David Kirkby wrote: > ALAN MELIA wrote: >> It is possible the crystal has succumbed to a mechanical fatigue. To >> check I used an old relay coil with a ferrite rod stuffed through it >> and tuned to 32.6khz. If you have a sensitive enough counter you may >> be able to measure this without an amp in line. (2% is a long way out >> !) It could also be the trimmer capacitor that has failed. I doubt >> there is much more mechanical, other than a dodgy solder joint. > > >> In all probability it will be the bane of all lovers of old >> electronics....the power supply electrolytic capacitors......remember >> battery quartz clocks run slow or fast as the batt runs out. > >> Alan G3NYK > > It could be the battery is low. There clearly is a battery backup, and > there is something on the clock which implies the holdover period is > about 4 days. (I forget the exact wording). Clearly if there is a > power failure, the clock must still rotate to keep accurate. > > I assume the battery is constantly charged by the incoming supply. > Given the age of the battery (> 17 years), it is unlikely to be in > good condition! But it should be charged all the time. But perhaps > even when charged, its voltage is very different to what it should be. > > I would not have thought a trimmer cap going open-circuit could have > induced a 2% change. That seems an awful lot. > If the trimmer in in series with the crystal and not shunted by another capacitor then the crystal will no longer control the oscillator frequency. 0.1pF or 0.01pF in series with a tuning fork crystal instead of the nominal value (20pf?) will make a singnificant difference. > Thanks for the idea of the ferrite rod. > > Dave > Bruce >> --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> wrote: >> >>> From: Dr. David Kirkby <david.kirkby@onetel.net> >>> Subject: [time-nuts] Can a quartz crystal go off by 2% ? >>> To: "Discussion of precise time and frequency measurement" >>> <time-nuts@febo.com> >>> Date: Monday, 28 December, 2009, 23:22 >>> I'm on the so-called 'Economy 7' >>> electric in the UK, where I'm supposed to get cheap electric >>> from 0030 to 0730 - i.e. a 7 hour period when electricity >>> demand is low. I'm no longer heating by electric, but do run >>> some computers 24/7. It's not totally clear whether this >>> saves me money or costs me money, as I pay a higher price >>> per unit during the expensive period, to compensate for the >>> fact I get it cheap for 7 hours. But I run some computers >>> 24/7. I guess I should do the maths and work it out. Apart >>> from some heaters in the garage, which are very rarely used, >>> I no longer heat with it. >>> >>> The time when the electric is cheap is set by a clock, >>> which rotates once/day. It says on it "quartz" somewhere, so >>> it must be regulated by a crystal and not from the 50 Hz >>> supply, which would be pretty useless, as the clock would go >>> wrong if there was ever a power failure. The clock has not >>> been changed in the 17 years I've lived at my house, though >>> the meter has on a couple of occasions. >>> >>> The clock used to keep accurate, but now it looses time >>> about 30 minutes/day. I wrote a computer program to predict >>> when the electric is cheap, so we can schedule when things >>> like the washing machine, dishwasher, Hoover etc are used. >>> Even cooking to a certain extent, if it's convenient, though >>> our life does not revolve around the cheap electric. >>> >>> I'm wondering if this is a mechanical fault in the clock, >>> or whether the crystal has developed a fault. It's clearly >>> well outside any tolerance or aging process of any crystal - >>> even the cheapest ones. >>> >>> I've not done any very extensive tests, but the error does >>> not appear to be constant. Hence every month or so I need to >>> produce a new table, as my predictions get less accurate >>> with time. Since one can only read the clock to an accuracy >>> of about 15 minutes, it's not easy to know how far it is >>> out. Sometimes we hear the contactor go over, as this is >>> supposed to then power the storage heaters, which we no long >>> use. >>> >>> Dave >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Bruce Griffiths wrote: > If the trimmer in in series with the crystal and not shunted by another > capacitor then the crystal will no longer control the oscillator frequency. > 0.1pF or 0.01pF in series with a tuning fork crystal instead of the > nominal value (20pf?) will make a singnificant difference. >> Thanks for the idea of the ferrite rod. >> > Bruce Thank you. I guess thats a possible failure mechanism, though if there is no control, I'd doubt it would keep 98 % accurate. I would have expected it to stop. Dave

Hi Even with a tuning fork crystal, anything past about 0.2% is a very large changel. That's true for tuning and also true for normal aging. I suspect that something mechanical has happened. 1) A cracked crystal - unlikely 2).An electro magnet in the driving circuit no longer firing fully. a) Due to a bad magnet b) Due to low power c) Due to a dying chip 3) A worn escarpment. Time to get it replaced .... Bob On Dec 28, 2009, at 6:22 PM, Dr. David Kirkby wrote: > I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to get cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity demand is low. I'm no longer heating by electric, but do run some computers 24/7. It's not totally clear whether this saves me money or costs me money, as I pay a higher price per unit during the expensive period, to compensate for the fact I get it cheap for 7 hours. But I run some computers 24/7. I guess I should do the maths and work it out. Apart from some heaters in the garage, which are very rarely used, I no longer heat with it. > > The time when the electric is cheap is set by a clock, which rotates once/day. It says on it "quartz" somewhere, so it must be regulated by a crystal and not from the 50 Hz supply, which would be pretty useless, as the clock would go wrong if there was ever a power failure. The clock has not been changed in the 17 years I've lived at my house, though the meter has on a couple of occasions. > > The clock used to keep accurate, but now it looses time about 30 minutes/day. I wrote a computer program to predict when the electric is cheap, so we can schedule when things like the washing machine, dishwasher, Hoover etc are used. Even cooking to a certain extent, if it's convenient, though our life does not revolve around the cheap electric. > > I'm wondering if this is a mechanical fault in the clock, or whether the crystal has developed a fault. It's clearly well outside any tolerance or aging process of any crystal - even the cheapest ones. > > I've not done any very extensive tests, but the error does not appear to be constant. Hence every month or so I need to produce a new table, as my predictions get less accurate with time. Since one can only read the clock to an accuracy of about 15 minutes, it's not easy to know how far it is out. Sometimes we hear the contactor go over, as this is supposed to then power the storage heaters, which we no long use. > > Dave > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Hi David at 17 years the probably NiCd batts may have one at zero volts and the charge is constant curent so the clock supply will not be held up by the charger. My timer used alkalines and I replaced every 5 years. Alan G3NYK --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> wrote: > From: Dr. David Kirkby <david.kirkby@onetel.net> > Subject: Re: [time-nuts] Can a quartz crystal go off by 2% ? > To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> > Date: Monday, 28 December, 2009, 23:58 > ALAN MELIA wrote: > > It is possible the crystal has succumbed to a > mechanical fatigue. To check I used an old relay coil with a > ferrite rod stuffed through it and tuned to 32.6khz. If you > have a sensitive enough counter you may be able to measure > this without an amp in line. (2% is a long way out !) It > could also be the trimmer capacitor that has failed. I doubt > there is much more mechanical, other than a dodgy solder > joint. > > > > In all probability it will be the bane of all lovers > of old electronics....the power supply electrolytic > capacitors......remember battery quartz clocks run slow or > fast as the batt runs out. > > > Alan G3NYK > > It could be the battery is low. There clearly is a battery > backup, and there is > something on the clock which implies the holdover period is > about 4 days. (I > forget the exact wording). Clearly if there is a power > failure, the clock must > still rotate to keep accurate. > > I assume the battery is constantly charged by the incoming > supply. Given the age > of the battery (> 17 years), it is unlikely to be in > good condition! But it > should be charged all the time. But perhaps even when > charged, its voltage is > very different to what it should be. > > I would not have thought a trimmer cap going open-circuit > could have induced a > 2% change. That seems an awful lot. > > Thanks for the idea of the ferrite rod. > > Dave > > > --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> > wrote: > > > >> From: Dr. David Kirkby <david.kirkby@onetel.net> > >> Subject: [time-nuts] Can a quartz crystal go off > by 2% ? > >> To: "Discussion of precise time and frequency > measurement" <time-nuts@febo.com> > >> Date: Monday, 28 December, 2009, 23:22 > >> I'm on the so-called 'Economy 7' > >> electric in the UK, where I'm supposed to get > cheap electric > >> from 0030 to 0730 - i.e. a 7 hour period when > electricity > >> demand is low. I'm no longer heating by electric, > but do run > >> some computers 24/7. It's not totally clear > whether this > >> saves me money or costs me money, as I pay a > higher price > >> per unit during the expensive period, to > compensate for the > >> fact I get it cheap for 7 hours. But I run some > computers > >> 24/7. I guess I should do the maths and work it > out. Apart > >> from some heaters in the garage, which are very > rarely used, > >> I no longer heat with it. > >> > >> The time when the electric is cheap is set by a > clock, > >> which rotates once/day. It says on it "quartz" > somewhere, so > >> it must be regulated by a crystal and not from the > 50 Hz > >> supply, which would be pretty useless, as the > clock would go > >> wrong if there was ever a power failure. The clock > has not > >> been changed in the 17 years I've lived at my > house, though > >> the meter has on a couple of occasions. > >> > >> The clock used to keep accurate, but now it looses > time > >> about 30 minutes/day. I wrote a computer program > to predict > >> when the electric is cheap, so we can schedule > when things > >> like the washing machine, dishwasher, Hoover etc > are used. > >> Even cooking to a certain extent, if it's > convenient, though > >> our life does not revolve around the cheap > electric. > >> > >> I'm wondering if this is a mechanical fault in the > clock, > >> or whether the crystal has developed a fault. It's > clearly > >> well outside any tolerance or aging process of any > crystal - > >> even the cheapest ones. > >> > >> I've not done any very extensive tests, but the > error does > >> not appear to be constant. Hence every month or so > I need to > >> produce a new table, as my predictions get less > accurate > >> with time. Since one can only read the clock to an > accuracy > >> of about 15 minutes, it's not easy to know how far > it is > >> out. Sometimes we hear the contactor go over, as > this is > >> supposed to then power the storage heaters, which > we no long > >> use. > >> > >> Dave > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Bob Camp wrote: > Hi > > Even with a tuning fork crystal, anything past about 0.2% is a very large changel. That's true for tuning and also true for normal aging. > > I suspect that something mechanical has happened. > > 1) A cracked crystal - unlikely > 2).An electro magnet in the driving circuit no longer firing fully. > a) Due to a bad magnet > b) Due to low power > c) Due to a dying chip > 3) A worn escarpment. Thank you Bob. > Time to get it replaced .... No, I'm quite happy to get cheap electric during the day some times! It's more useful than having it in the middle of the night. So I'm not concerned over this, but just interested what might be the problem with it. > > Bob Dave

ALAN MELIA wrote: > Hi David at 17 years the probably NiCd batts may have one at zero volts and the charge is constant curent so the clock supply will not be held up by the charger. My timer used alkalines and I replaced every 5 years. > > Alan G3NYK A recent power failure did not cause the clock to stop, so some battery power must exist, but I believe the clock may have run a bit slower during that period, as there was a bit of a kink in the graph, but due to the limited amount of data, its hard to be precise about this. But I believe the power failure did throw my estimates off a bit more than usual. Dave > --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> wrote: > >> From: Dr. David Kirkby <david.kirkby@onetel.net> >> Subject: Re: [time-nuts] Can a quartz crystal go off by 2% ? >> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> >> Date: Monday, 28 December, 2009, 23:58 >> ALAN MELIA wrote: >>> It is possible the crystal has succumbed to a >> mechanical fatigue. To check I used an old relay coil with a >> ferrite rod stuffed through it and tuned to 32.6khz. If you >> have a sensitive enough counter you may be able to measure >> this without an amp in line. (2% is a long way out !) It >> could also be the trimmer capacitor that has failed. I doubt >> there is much more mechanical, other than a dodgy solder >> joint. >> >> >>> In all probability it will be the bane of all lovers >> of old electronics....the power supply electrolytic >> capacitors......remember battery quartz clocks run slow or >> fast as the batt runs out. >> >>> Alan G3NYK >> It could be the battery is low. There clearly is a battery >> backup, and there is >> something on the clock which implies the holdover period is >> about 4 days. (I >> forget the exact wording). Clearly if there is a power >> failure, the clock must >> still rotate to keep accurate. >> >> I assume the battery is constantly charged by the incoming >> supply. Given the age >> of the battery (> 17 years), it is unlikely to be in >> good condition! But it >> should be charged all the time. But perhaps even when >> charged, its voltage is >> very different to what it should be. >> >> I would not have thought a trimmer cap going open-circuit >> could have induced a >> 2% change. That seems an awful lot. >> >> Thanks for the idea of the ferrite rod. >> >> Dave >> >>> --- On Mon, 28/12/09, Dr. David Kirkby <david.kirkby@onetel.net> >> wrote: >>>> From: Dr. David Kirkby <david.kirkby@onetel.net> >>>> Subject: [time-nuts] Can a quartz crystal go off >> by 2% ? >>>> To: "Discussion of precise time and frequency >> measurement" <time-nuts@febo.com> >>>> Date: Monday, 28 December, 2009, 23:22 >>>> I'm on the so-called 'Economy 7' >>>> electric in the UK, where I'm supposed to get >> cheap electric >>>> from 0030 to 0730 - i.e. a 7 hour period when >> electricity >>>> demand is low. I'm no longer heating by electric, >> but do run >>>> some computers 24/7. It's not totally clear >> whether this >>>> saves me money or costs me money, as I pay a >> higher price >>>> per unit during the expensive period, to >> compensate for the >>>> fact I get it cheap for 7 hours. But I run some >> computers >>>> 24/7. I guess I should do the maths and work it >> out. Apart >>>> from some heaters in the garage, which are very >> rarely used, >>>> I no longer heat with it. >>>> >>>> The time when the electric is cheap is set by a >> clock, >>>> which rotates once/day. It says on it "quartz" >> somewhere, so >>>> it must be regulated by a crystal and not from the >> 50 Hz >>>> supply, which would be pretty useless, as the >> clock would go >>>> wrong if there was ever a power failure. The clock >> has not >>>> been changed in the 17 years I've lived at my >> house, though >>>> the meter has on a couple of occasions. >>>> >>>> The clock used to keep accurate, but now it looses >> time >>>> about 30 minutes/day. I wrote a computer program >> to predict >>>> when the electric is cheap, so we can schedule >> when things >>>> like the washing machine, dishwasher, Hoover etc >> are used. >>>> Even cooking to a certain extent, if it's >> convenient, though >>>> our life does not revolve around the cheap >> electric. >>>> I'm wondering if this is a mechanical fault in the >> clock, >>>> or whether the crystal has developed a fault. It's >> clearly >>>> well outside any tolerance or aging process of any >> crystal - >>>> even the cheapest ones. >>>> >>>> I've not done any very extensive tests, but the >> error does >>>> not appear to be constant. Hence every month or so >> I need to >>>> produce a new table, as my predictions get less >> accurate >>>> with time. Since one can only read the clock to an >> accuracy >>>> of about 15 minutes, it's not easy to know how far >> it is >>>> out. Sometimes we hear the contactor go over, as >> this is >>>> supposed to then power the storage heaters, which >> we no long >>>> use. >>>> >>>> Dave >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@febo.com >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn, Cumbria). You would need to have some sort of automated system to accommodate daylight savings switchovers in Spring and Autumn. That said, I would have thought once synchronised, they would "tick" off the 50 Hz supply. Rob Kimberley -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Dr. David Kirkby Sent: 28 December 2009 23:22 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Can a quartz crystal go off by 2% ? I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to get cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity demand is low. I'm no longer heating by electric, but do run some computers 24/7. It's not totally clear whether this saves me money or costs me money, as I pay a higher price per unit during the expensive period, to compensate for the fact I get it cheap for 7 hours. But I run some computers 24/7. I guess I should do the maths and work it out. Apart from some heaters in the garage, which are very rarely used, I no longer heat with it. The time when the electric is cheap is set by a clock, which rotates once/day. It says on it "quartz" somewhere, so it must be regulated by a crystal and not from the 50 Hz supply, which would be pretty useless, as the clock would go wrong if there was ever a power failure. The clock has not been changed in the 17 years I've lived at my house, though the meter has on a couple of occasions. The clock used to keep accurate, but now it looses time about 30 minutes/day. I wrote a computer program to predict when the electric is cheap, so we can schedule when things like the washing machine, dishwasher, Hoover etc are used. Even cooking to a certain extent, if it's convenient, though our life does not revolve around the cheap electric. I'm wondering if this is a mechanical fault in the clock, or whether the crystal has developed a fault. It's clearly well outside any tolerance or aging process of any crystal - even the cheapest ones. I've not done any very extensive tests, but the error does not appear to be constant. Hence every month or so I need to produce a new table, as my predictions get less accurate with time. Since one can only read the clock to an accuracy of about 15 minutes, it's not easy to know how far it is out. Sometimes we hear the contactor go over, as this is supposed to then power the storage heaters, which we no long use. Dave _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.